In an interview set to air this fall, Swift told ABC News' "Nightline" that she was in the studio with producers Max Martin and Johan Shellback on her upcoming album, Red, when the friend of an ex-boyfriend (Swift didn't want to name him) walked in.

"[My friend] starts talking about how he's heard [my ex and I] were getting back together and that was not the case," Swift says in the teaser clip. "When he leaves, Max and Johan are like, 'So what's the story behind that?' And so I start telling them the story of 'break up, get back together, break up, get back together,' just, ugh, the worst."

The trio quickly realized that story had to be a song. "Max says, 'This is what we're writing; we're writing this song,' " Swift recalls. "And I picked up the guitar and just started singing 'we are never.' It just happened so fast. It was so much fun."

While the empowering message isn't new for Swift, the lead single might sound a little different to her hard-core fans, thanks to her hooking up with Red's lead producer, Martin, the go-to guy for pop superstars like Britney Spears ("Hold It Against Me," "Till The World Ends"), Katy Perry ("Part of Me," "Teenage Dream") and Justin Bieber ("Beauty and the Beat").